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Thread: Why are turbo's more tunable?

  
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    Why are turbo's more tunable?

    Everyone says turbo cars are more tunable but don't really understand. Take for example the coupe Turbo and coupe 2.2. As standard the Turbo is a lot faster but by adding a turbo to the 2.2 would this not make it faster than the 2.0 turbo? Then once the 2.2 has got its turbo, it would be open to mods like the 2.0 hence they will be equally tunable.

    I know there is more to it than what I've described but that's what I understand at the moment. Some please educate me

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    U have made a good point there chap, but the cost would be astronomical, and in my view probably not worth it. :?

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    it's not quite as simple as glueing on a turbo. alot of other parts would have to be uprated, which wouldn't be cheap..

    i'm not sure anybody makes a turbo for the 2.2 either
    Visit our-formats.com for creative design services

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    Turbos are easier and cheaper to tune would be a true statement.

    N/A engines take more work which makes it more expensive. But a well tuned N/A engine can be alot better to drive and race with.

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    Turboing a car has always been bandied about in the industry as easy power. And it IS up to a point. That is the point where a 'lo-blow' non-intercooler conversion was feasible, meaning no big mods to the intake etc. Courtenay used to do similar tunes when they first started out, hence they are still known to lots of VX heads as Courtenay Turbos.

    I seriously looked at turboing my old car, a 2.0 litre 8v Megane, as it shared a lot of the F3R engine setup with the Volvo 480 Turbo Coupe, which had a 1.7 F3R engine with a Porsche tune up and turbo setup.

    A few factors came to light when we looked at this as a SERIOUS power upgrade.

    1. You need an intercooler for a decent allowance of boost pressure and a decent power gain, this needs making and mounting in front of the radiator. Budget on about £600 for a custom intercooler and piping and mods.
    2. You need a suitable turbo and oil piping to it. Budget another £500 easily, depending on whether you plan on doing the mods to the engine yourself. I was gonna use a Mocal adaptor for the turbo oil feeds, they retail at £70 apiece, but you still need custom made pipework to and from the turbo.
    3. You need to lower compression for decent boost levels. I opted to buy a spacer gasket, £200 to have one made as a one off in stainless steel. Thereafter they are £75 apiece, as they have to make custom tooling for each one (can you see how Courtenay did their conversions now? One off cost for the 1st gasket spacer, then cheaper for the rest of the conversions). If you want to use special low compression pistons add about £300 to the equation, without labour costs for fitting and replacing any gudgeon pins, bearings etc etc etc
    4. Can your drivetrain take the strain? The Renault gearbox was weak and wouldn't tolerate the torque. Budget for a top spec clutch and high tolerance gearbox rebuild (I had this done after it lunched a synchro anyway, £1400 fitted) Remember that VX boxes are limited by their torque too. I smashed my standard clutch on a Nova with a 25% N/A power increase (it came out in little pieces when we changed it)
    5. Still with me? OK the car now has a big power hike, can the engine take the heat of forced induction? A lot can't. Add an oil cooler £250 all in (self fitted). The less heat the more power.
    6. OK. All done? Now ask Mr Insurance for a quote. He'll want it to stop. Judge on an upgrade above and beyond a 'proper' turbo to keep their minds at rest and your bank balance in the black each month £1000 for a nice big front brake conversion. Insurance will still be expensive as it is a modified car (my Megane was quoted to be provisional group 17 if I went ahead with the mods)

    All in all, about £2500+ fitted and modded in my driveway, over months and still got to worry about wrecking the standard driveshafts etc. I still got a Turbo though

    It's sitting under the bonnet of my SRi T and it is 2 groups lower than my Megane would have been. Something to think about before going mod mental

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    Quote Originally Posted by Steve
    Turboing a car has always been bandied about in the industry as easy power. And it IS up to a point. That is the point where a 'lo-blow' non-intercooler conversion was feasible, meaning no big mods to the intake etc. Courtenay used to do similar tunes when they first started out, hence they are still known to lots of VX heads as Courtenay Turbos.

    I seriously looked at turboing my old car, a 2.0 litre 8v Megane, as it shared a lot of the F3R engine setup with the Volvo 480 Turbo Coupe, which had a 1.7 F3R engine with a Porsche tune up and turbo setup.

    A few factors came to light when we looked at this as a SERIOUS power upgrade.

    1. You need an intercooler for a decent allowance of boost pressure and a decent power gain, this needs making and mounting in front of the radiator. Budget on about £600 for a custom intercooler and piping and mods.
    2. You need a suitable turbo and oil piping to it. Budget another £500 easily, depending on whether you plan on doing the mods to the engine yourself. I was gonna use a Mocal adaptor for the turbo oil feeds, they retail at £70 apiece, but you still need custom made pipework to and from the turbo.
    3. You need to lower compression for decent boost levels. I opted to buy a spacer gasket, £200 to have one made as a one off in stainless steel. Thereafter they are £75 apiece, as they have to make custom tooling for each one (can you see how Courtenay did their conversions now? One off cost for the 1st gasket spacer, then cheaper for the rest of the conversions). If you want to use special low compression pistons add about £300 to the equation, without labour costs for fitting and replacing any gudgeon pins, bearings etc etc etc
    4. Can your drivetrain take the strain? The Renault gearbox was weak and wouldn't tolerate the torque. Budget for a top spec clutch and high tolerance gearbox rebuild (I had this done after it lunched a synchro anyway, £1400 fitted) Remember that VX boxes are limited by their torque too. I smashed my standard clutch on a Nova with a 25% N/A power increase (it came out in little pieces when we changed it)
    5. Still with me? OK the car now has a big power hike, can the engine take the heat of forced induction? A lot can't. Add an oil cooler £250 all in (self fitted). The less heat the more power.
    6. OK. All done? Now ask Mr Insurance for a quote. He'll want it to stop. Judge on an upgrade above and beyond a 'proper' turbo to keep their minds at rest and your bank balance in the black each month £1000 for a nice big front brake conversion. Insurance will still be expensive as it is a modified car (my Megane was quoted to be provisional group 17 if I went ahead with the mods)

    All in all, about £2500+ fitted and modded in my driveway, over months and still got to worry about wrecking the standard driveshafts etc. I still got a Turbo though

    It's sitting under the bonnet of my SRi T and it is 2 groups lower than my Megane would have been. Something to think about before going mod mental
    Thank you for that and i totally understand that with a turbo car, all other bits of the car must be upgraded to cope with the extra power of the car. However, on a turbo, if the extra bits have now reached their limit because of the turbo then modifying the car for extra power would be the same as a NA. Parts will still need to be replaced.

    I.e. An NA car may have gearbox type A as it can cope with the power from that car.
    A Turbo car may have gearbox type B as A is not strong enough but B is strong enough for the Turbo.

    Whether the NA car gets a turbo, or the Turbo car gets a bigger turbo would it mean the gearbox still needs upgrading. The gearbox for the original Turbo car maybe more expensive but still don't see why Turbo cars are more tunable unless the uprated parts fitted to a Turbo as standard can cope above and beyond the standard power of the car and thus allowing slack space for more power to be modded on. Thanks

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    Quote Originally Posted by mshah
    don't see why Turbo cars are more tunable unless the uprated parts fitted to a Turbo as standard can cope above and beyond the standard power of the car and thus allowing slack space for more power to be modded on.
    And this is indeed what most car manufacturers do. If all car engines we tuned to the max before they got to you, then you would see a lot more standard cars with engine problems, especially ones that arn't looked after.

    The manufacturers have to allow for lack of servicing etc when the build a car so there is always going to be improvements that can be made.

    The trick though its to find how far you can go before you need to start uprating things like the gerabox, driveshafts etc.

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    The Z20LET was designed from the outset to cope with forced induction. Engine design goes deeper than just what you bolt onto it. A good example is with a 'standard' turbo engine, it will be built with lowered compression ratio and possibly different piston design. Components will be designed for high torque at lower RPMs ,which is inherent in a turbo, ie stronger, heavier crank and stronger conrods. The engine in something like the Civic Type R with a high revving desing will be designed to hold together at high RPM, lighter, shorter throw crank, lighter rods and stronger gudgeon pins etc.

    All production engines have a built in tolerance, as do the drive components. An F23 gearbox can cope with 230 lbs of torque, but the Z20LET doesn't produce anything like that as standard. When you want to tune a turbo engine you 'just' wind up the boost to get more air in and add more fuel. Easy. On a N/A engine you will need to find another way of getting more air and fuel to burn in order to produce more power. To do this you have to alter the cam timings and lifts, rev higher, use the scavenging effects of tuned exhausts. A N/A is just as tuneable. It is just far far more expensive.

    The 2.0 litre N/A in the Coupe Astra BTCC car produces as much power, well probably (a lot) more than the turbo 2.0 litre production model. However, it probably costs more to build that engine than the cost of a whole 'normal' Astra

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    Quote Originally Posted by Steve
    A N/A is just as tuneable. It is just far far more expensive.
    I think that has answered my question. It's not the fact that turbo's are more tunable, its the fact that it's cheaper. Thank you everyone who replied!

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